I occasionally post comments on Terracotta Pot Irrigation as I've been exploring and experimenting with the method for some time.
It's a bit of a passion.
On my very sandy soil they've proven the only approach that works while saving water such that I'm more or less irrigating from my one 3,000 litre tank and only supplementing occasionally.
My key lessons are:
- Pot size: at least 20 cm in diameter
- Routine top up: every 3-4 days usually despite the weather conditions.My pots will take 4 days to empty whether it rains or not.Nor does evaporation seem to impact much on this rate.
- White, heavy white coloured stoneware plates for lids. Lighter or smaller plates will only be upended by crows.
- Rather than cover the drainage holes with a wee tile and sealant, I find it preferable to lay down a layer of grout across the bottom of each pot because by sealing the whole bottom, the rate of irrigation is slowed even further by up to 25%. Water is forced by gravity to disperse through the sides alone.
- Also test your 'sealed' pot to see if it does hold water without leaking and, conversely, that the terracotta is permeable. Even raw terracotta pots, seemingly from the same batch/same pottery may often not leach water -- I guess because of differences in clay structure and grog.To bury these is a waste of time and space. Grow plants in 'em instead.
My current focus is exploring the most effective and water efficient distance between pots given my soil type...while experimenting with planting patterns and sowing distances around each pot's perimeter.
I'm thinking that a Terracotta Pot Irrigated Garden requires a different template than the standard rectangular bed pattern. A wave pattern...
While this research argues that even small pots can maintain a wet front 60 cms from the pot for a period of 10 days, the factors impacting on distance are variables such as soil type and clay mix.Since I need to refill mine at shorter intervals, 10 days of constant irrigation from one pot full of water aint an option.
Of related interest are elements such as the diameter of the pot vs its depth...but my feeling is that a key factor is the surface areas on the sides of the pot that are responsive to the pressure of gravity. That means that only part of the 'walls' will be wet enough to irrigate.
Consider a wet sponge and how water will always settle at the bottom of the sponge with varying degrees of wetness the deeper you go....while the driest area will be at the top.
These pots follow the same rules of Physics.